A senior scientist here on DU had this theory that he linked to here on DU which is similar to what I just said that the foundations of the planet we live on is not a dense rock as you say but more like a fluid process of liquid, rock and energy....
Here he says:
We use that as a cover, to prevent the widespread panic that would ensue if it were commonly known that their very foundations were not foundations at all, merely thin pieces of onionskin adrift on pools of molten lava.
He again says that the very foundations of the planet we live on are not foundations at all and are "merely thin pieces of onionskin adrift on pools of molten lava."
Excerpts from his website:
The Society for the Prevention of Plate Tectonics
A.k.a. SoPrePlaTec, and pronounced "soapy platex", is dedicated to the prevention of plate movements on planets. We attempt to use technology or any other useful means to prevent continental drift and the associated disastrous earthquakes and volcanoes.
Also, I must ask you to keep any knowledge of SPCD confidential. The world at large believes that oil companies are searching for gasoline for their Suburbans and Kawasakis, and for CO2 to keep the atmosphere warm. We use that as a cover, to prevent the widespread panic that would ensue if it were commonly known that their very foundations were not foundations at all, merely thin pieces of onionskin adrift on pools of molten lava.
http://www.wimble.org/SoPrePlaTec/preventionhome.html